Debridement is used to remove from the skin. necrotic tissue wrinkles bacteria a cancerous tumor

I think the correct answer is necrotic tissue. Debridement is the removal of unhealthy tissue from a wound or skin to promote healing. It can be done using surgical methods, chemical, mechanical or autolytic (own body process)removal of the tissue. The unhealthy tissue may be a damaged, dead or infected tissue that is removed to improve the potential of healing of the remaining healthy tissue.

C. gemstones they are the only non metallic mineral from the list.